Refrigeration system



Dec. 27, 19 60 c. E. DE TURK REFRIGERATION SYSTEM 2 Sheets-Sheet 1 FiledApril 8, 1957 INVENTOR. (/IZV/A E. 05 Tl/XK Amwr Dec. 27, 1960 c. E. DETURK 2,966,042

REFRIGERATION SYSTEM Filed April 8, 1957 2 Sheets-Sheet? F/q. 7: gamwascents Patented Dec. 27, 1960 ice REFRIGERATION SYSTEM Calvin E. DeTurk, Drexel Hill, Pa., assignor to Philco Corporation, Philadelphia,Pa., a corporation of Pennsylvania Filed Apr. 8, 1957, Ser. No. 651,449

Claims. (Cl. 62-156) The present invention relates to refrigerationapparatus and, more particularly, to domestic refrigerators of the typehaving evaporator means adapted to freeze food and water as well as tomaintain such food and water at freezing temperatures, and whichevaporator means is further adapted to be heated, at desired orpredetermined intervals, to effect removal of frost therefrom.

With a refrigerator of the above-mentioned variety, it has been known tosupport food, which has been previously frozen, by means serving toprevent undue rise of the temperature of the supported food duringheating of the evaporator to defrost the same. However, in the initialfreezing and subsequent storage of ice, and also of certain foodmaterials, by use of conventional receptacles or ice trays, it has beenthe practice to establish optimum thermal contact of such trays with theevaporator in order to ensure more rapid freezing of the contentsthereof. Ice, for example, thus stored is of course unharmed by partialmelting of the same, as often occurs during the defrost period. It isknown, however, that loaded trays represent a considerable thermal mass,which in contact with the evaporator means while defrosting, effects asubstantial increase in the time required for defrosting. This excessivetime is objectionable in that it contributes to undue warm-up of frozenfood while defrosting takes place.

It is therefore an important objective of the invention to provide novelmeans for overcoming the above noted objection.

In accordance with the general features of the invention, there isprovided means in association with a defrostable cooling element, andoperable to provide substantially less than optimum heat exchangerelation be tween a receptacle and such element while defrosting thelatter.

In the achievement of the foregoing and other objec tives a preferredembodiment of the invention comprises means which, during normalrefrigerating operation, provides direct contact of ice trays with theevaporator, said means being operable with the defrosting means to breakthe ice bond between said trays and said evaporator and to move thetrays substantially out of contact with the evaporator, therebyeffectively lessening the heat required for defrosting and minimizing,accordingly, the degree of warm-up of foods refrigerated by theevaporator.

The novel features of the invention, and the manner in which theforegoing and other objectives and advantages are best achieved, will beapparent from the following description taken in view of theaccompanying drawings in which:

Figure 1 is a perspective view of a refrigerator embodying theinvention;

Figure 2 is a view, on a somewhat enlarged scale, of a portion of therefrigerator shown in Figure 1, with parts broken away;

Figure 3 is a somewhat diagrammatic elevational view of apparatus shownin Figure 2;

Figure 4 is a view similar to Figure 3 and showing an operationalfeature of the invention;

Figure 5 is a diagrammatic showing of a refrigerating system embodyingthe invention;

Figure 6 is a fragmentary showing, similar to Figure 5, of analternative embodiment of the invention;

Figure 7 is a fragmentary showing similar to Figure 5, of still anotherembodiment of the invention; and

Figure 8 is a fragmentary showing, similar to Figure 2, of an additionalembodiment of the invention.

Now making more particular reference to the drawings, it will be seen inFigure 1 that the invention is embodied in a domestic or householdrefrigerator which comprises a cabinet 10 having an outer shell 11 and apair of inner liners 12 and 13, said shell and liners being spaced andinsulated from each other by means of suitable insulation 14 (see alsoFigure 2). As is customary, breaker strips 15 of low thermalconductivity extend about the forward edge of the cabinet and bridge thegaps between the shell and inner liners. These liners define twoisolated zones which constitute a lower compartment 16 and an uppercompartment 17. Insulated doors 18 and 19 of usual construction andincluding gasket strips 20, are, respectively, employed to close thefront access opening of each of said compartments.

The lower compartment 16 is utilized for the storage of frozen food (notshown) and ice trays 24, as well as for the freezing of these articles.According to usual practice, compartment 16 is supplied with slidabledrawers or racks 25 for supporting the food out of contact withconventional evaporator means provided in this compartment, said meansincluding a suitable refrigerated shelf 26 provided with refrigerantconduit means 32 in heat exchange relation therewith and (see alsoFigure 5) adapted for the support of ice trays 24 both to be frozen andstored. The upper compartment 17 is effectively cooled and maintained atcooling or non-freezing temperatures by means of an evaporator 27, whichin the illustrated embodiment, comprises a generally rectangular etallicsheet 28 provided with conduit means 29 for circulation of refrigerantin heat exchange relation with said sheet. The plate evaporator 27 isconveniently mounted in a vertical position close to the rear wall andspans substantially the width of the compartment as defined by,confronting side walls of said liner so as to present a comparativelylarge surface exposed to the air within said upper compartment.

No-w referring to Figure 2, and in particular accordance with apreferred embodiment of the present invention, the lower side of theevaporator ice freezing shelf 26 is provided with a horizontallydisposed rotatable shaft 30 having spaced axially thereof a plurality ofcam elements 34; rotatable support of the shaft is provided by suitablebracket means 31 afiixed to refrigerated shelf 26. Intermediate eachsupported tray 24, there being shown but one tray for illustrativepurposes, and cam element 34 is an aperture 35 formed in ice freezingshelf 26. Portions of cam elements 34 are respectively extensible andretractable through apertures 35 operably to engage each tray 24,tiltably to raise or lower the same about evaporator contacting endportions of the trays as fulcrums, and in response to operation of thecrank 36 provided at the end of rotatable shaft 30. Although theillustrated embodiments of the invention include apparatus for tiltingthe trays out of substantial thermal contact, it is to be understoodthat additional cam elements may be provided to raise the trays, andsuspend the same, entirely out of contact with the evaporator or, incertain embodiments, the trays could be shifted laterally. Operation ofcrank 36 is accomplished through the agency of a bar 37 pivotallyaflixed thereto, said bar being longitudinally actuatable by solenoidmeans 38, thereby to rotate shaft 30 and its camming elements 34 asdescribed. Means in novel association with the aforesaid solenoid means38, for energizing the same in response to initiation of the defrostcycle, will be hereinafter more fully explained.

As seen further in Figure 5, evaporator shelfzfiand the upper plateevaporator 27 form parts of an automatically defrostable refrigeratingsystem which includes a motor compressor 39 and a condenser 40.Preferably, although not necessarily, the refrigerating systemillustrated is made in accordance with that disclosed and claimed inU.S. patent to E. W. Zearfoss, No. 2,627,730, issued February 10, 1953,and assigned to the assignee of the present invention. On-and-oficycling of the motor compressor 39 is controlled by means of a device 44of the known bellows type having a feeler tube 45 which may, forexample, be arranged in heat exchange relation (not shown) with theplate evaporator 27 so that the temperature of the latter influences theoperation of the device to actuate a switch element 46 for opening andclosing contacts 47 in the electrical circuit, which is adapted tosupply electrical energy to the motor compressor 39. Preferably,although not necessarily, the control device 44 is such that when thetemperature of plate evaporator 27 reaches the lower end of itspredetermined operating temperature range switch element 46 is moved toopen the circuit to deenergize motor compressor 39, and when thetemperature of the evaporator reaches the upper end of the range theswitch element is actuated to close the circuit to energize the motorcompressor.

Evrporators 26 and 27 are connected in series flow circuit by means of aconduit 48 which leads from the outlet of plate evaporator 27 to theinlet of evaporator 26. The outlet of evaporator 26 communicates througha conduit section with an accumulator 49 which, in turn, communicateswith the inlet side of compressor 39 through a conduit section 50, andthe outlet side of the compressor is connected with the inlet end of thecondenser through a conduit 54. A capillary tube arrangement 55 servesto connect the outlet end of condenser 40 with an accumulator device 56,said device being further connected to the plate evaporator 27 by meansof a suitable conduit 57. A by-pass connection or conduit 58 extendsfrom the compressor discharge conduit 54 to the aforementionedaccumulator device 56, and a solenoid actuated valve 59 in the by-passconnection 58 serves to open or close the same.

Inasmuch as operational details of the defrosting system illustrated arefully explained in the aforementioned Patent 2,627,730 no detaileddescription will be necessary. However, it is pointed out that thecontrol circuit of the illustrated refrigerating system includes asingle throw double pole switch 64, and the defrosting cycle isinitiated in response to closure of this switch, by suitable manual orautomatic means (not shown), regardless of the position of the contactsof the thermostatic switch device 44. Closing of the switch 64 placessolenoid actuated valve means 59 across line L (Figure therebyenergizing the same to open the valve and concurrently energizing thecompressor 39 with and modifying flow of refrigerant within the systemin such manner that defrosting of the evaporators take place.

In particular accordance with the invention the electrical solenoidmeans 38, hereinbefore referred to, is disposed in parallel circuitrywith the solenoid of valve 59 in such manner that initiation of thedefrost cycle through energization of solenoid valve 59 will energizethe solenoid means 38, thereby retracting bar 37 and op erating crank36. This operation of the crank rotates cams 34 through the openings 35in ice freezing shelf or evaporator 26, whereby cams 34 operably engageend portions of the ice trays 24 resting upon the shelf, as best seensomewhat diagrammatically in Figures 3 and 4, to lift the trays out ofsubstantial thermal contact with 4 a the evaporator. While lifting ofthe trays is sufficient to break the effective thermal contact, themovement is of such a nature as to prevent overflow or spilling of wateronto evaporator surfaces.

Upon completion of the defrost cycle and opening the defrosting switch64, solenoid valve 59 is deenergized, and the normal refrigerating cycleresumed. Concurrent with deenergization of the solenoid valve, the camactuator solenoid 38 1s deenergized whereupon the vertical weightcomponents of ice trays 24, or other suitable means, cause cams 34 toretract thereby again providing substantial thermal contact of the trayswith the ice freezing shelf.

Alternatively, as illustrated in Figure 6, the cam actu ator solenoid 38may be placed across the line L in series with a normally openbellows-actuated thermostatic switch 65 of known design having itsfeeler bulb 66 in thermal contact with, for example, the inlet conduit57 of the evaporator system. In such an arrangement then mostatic switch65 is so conditioned as to close, in response to a predeterminedelevated temperature characteristic of the defrost cycle, therebyenergizing the cam actuating solenoid 38 to elevate the trays in themanner hereinbefore described. .Return to normal operating temperaturesfollowing the defrost period will, of course, open the thermostaticswitch, in accordance with a predetermined lower temperature limit, anddeenergize the cam actuating solenoid to lower the trays into thermalcontact with the evaporator.

An additional embodiment is seen in Figure 7 wherein apparatus of thetype shown in Figure 6 has been somewhat modified by providing a directmechanical linkage between a suitable pressure responsive expansiole andretractable bellows 67 and the tray release mechanism. Actuatingpressure in the bellows 67 is determined by the sensing element orfeeler bulb 66 in contact with conduit 57 in the refrigerator circuit.In operation, ele vated temperatures characteristic of the defrostingcycle will cause the bellows to expand thereby operating the cam linkage34, 36, 37, to elevate the trays, in the manner hereinbefore described.Cessation of defrosting. characterized by reduced temperatures, willcause the bellows to contract thereby operating the cam linkage in thereverse direction to lower the trays into thermal contact with theevaporator.

Still another embodiment is shown in Figure 8, wherein the solenoidmeans has been disposed intermediate shell 11a, and liner 13a of thecabinet 19a, as indicated by reference character 38a. Individual camlinks 34:: disposed within perforations or apertures 3551 provided inthe evaporator shelf 26a are mounted for pivotal movement uponindividual pins 3e11, the latter being supported within downwardlyturned flange portions 35a of evaporator 26a. Operably connecting thecam links, as by pins 30b, to the operating solenoid is a connectinglink 37b adapted for horizontal, substantially linear movement, wherebyactuating the solenoid 38a with the defrosting means will rotate camlinks 34:: to lift the trays (not shown). Conversely, deenergization ofthe solenoid will reverse the movement of the linkage and lower thetrays.

While this description and the accompanying drawings are illustrative ofpreferred embodiments of the in vention, it will be recognized thatadditional changes and modifications may be made in the describedapparatus, without departing from the spirit of the invention as definedin the appended claims.

I claim:

1. A refrigerator comprising: an evaporator adapted to refrigerate attemperatures below freezing and hav ing provision for supportingreceptacles containing water or other material to be frozen; means fordefrosting said evaporator by subjecting. the latter to heat attemperatures above freezing; control means operative to initiate defrostof said evaporator; and means operative with said control means uponinitiation of the defrost to break the ice bond between said receptaclesand said evaporator and to move said receptacles substantially out ofcontact with said evaporator.

2. In combination with automatically defrostable refrigerator evaporatormeans having a tray supported in contact therewith, a rotatable memberdisposed adjacent said tray, a cam element carried by said rotatablemember in the region of said tray, said cam element being adaptedoperably to engage said tray and move the same in response to rotationof said rotatable member, control means operative to initiate defrostingof said evaporator means and means operative with said control meansupon initiation of defrosting to actuate said rotatable member to movethe tray.

3. In combination with a freezer compartment having a defrostableevaporator for maintaining below freezing temperatures in saidcompartment, said evaporator further being adapted to support a tray andhaving an aperture provided in the region of a supported tray,extensible and retractable cam means operable for movement through saidaperture into and out of contact with a supported tray to, respectively,elevate and lower such a tray out of or into contact with theevaporator, control means operative to initiate and terminate defrostingof the evaporator, and means for operating the cam means actuatable bysaid control means to initiate or terminate defrosting of theevaporator, respectively, to raise or lower the trays.

4. In a refrigerator having cooling means presenting a defrostablerefrigerating surface within said refrigerator, said surface being inhigh heat exchange relation with receptable means supported in contacttherewith, means for defrosting said cooling means, control meansoperative to actuate said means for defrosting, and means operable bysaid control means, upon actuation of said means for defrosting, forsupporting said receptacle means in relatively poor heat exchangerelation with said refrigerating surface.

5. In a refrigerating system including a defrostable cooling elementadapted to refrigerate a receptacle supported in contact therewith,control means operative to condition said cooling element for defrost,and means operative by said control means when the cooling element isconditioned for defrost to reduce the contacting area of a supportedreceptacle.

Anderson Sept. 13, 1955 Williams Feb. 21, 1956

